Carbonyl levels and survival rates in oral cancer cells exposed to cigarette smoke.

BACKGROUND: Cigarette smoke (CS) is the main inducer of oral cancer, increasing prevalence 4-7 times. MATERIALS AND METHODS: We examined SCC-25 and SCC-15 suitability for studying CS effects on oral cancer cells, measuring carbonyl levels for free radical-mediated CS effect on survival and time/CS dependence. RESULTS: Protein oxidation increased significantly during CS exposure. At all time points, carbonyl levels increased six-fold (p<0.001) in both cell lines. Cell viability decrease was time-dependent. Longer CS exposure led to higher cell mortality. At 120 min, SCC-25 cell survival reduction was 43.7%, (p<0.01). Propidium iodide (PI) assay results matched the Trypan blue assay showing a time-dependent cell viability decrease following CS exposure. At 120 min, cell survival reduction was 37% (p<0.05). CONCLUSION: Cell death is mediated by CS free radicals with pathological process occurring first. Oral cancer cell models SCC-25 and SCC-15 are suitable for studying CS-induced free radical-related damage, potentially leading to the pathogenesis of oral cancer.